1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device used, e.g., for the control of industrial motors and vehicle motors, etc.
2. Background Art
Japanese Laid-Open Patent Publication No. 2009-279661 discloses a wafer in which a central portion has been ground by means of a grinding stone so that the wafer is thinner in the central portion and thicker in the peripheral portion. The grinding of the central portion of the wafer is such that the semiconductor devices formed in that portion have the desired thickness. The peripheral portion of the wafer is not ground in order to maintain the strength of the wafer.
Grinding of a wafer by use of a grinding stone results in the production of grindings or chips. If grinding's are caught between the grinding stone and the wafer and yet the grinding operation continues, local cracks may form in the wafer. Such cracks are referred to as “chippings.” Crack propagation originating from these chippings can occur, which may result in breakage of the wafer, and chemical solution, etc. can be trapped on the wafer surface due to the chippings formed therein.